1. Field of the Invention
The present invention relates to a coupling link or fastening member for a mounting strap of a tire chain. The fastening member includes an introduction passage and an attachment passage for a counter or cooperating fastening member, with the introduction and attachment passages being interconnected by a guide passage, but otherwise being separated from one another by a hook arm portion that is provided with a securing element that narrows the attachment passage.
2. Description of the Prior Art
U.S. Pat. No. 4,542,779--Muller et al dated Sept. 24, 1985, which belongs to the assignee of the present application, discloses a fastening member of this general type. With this known fastening member, the securing element is formed by a rounded-off projection on the end of the hook arm. Between this arm end and the opposite wall, a guide portion of the guide passage is formed that extends at right angles to the introduction passage and to the attachment passage. Since this guide portion is perpendicular to the direction of insertion of a cooperating fastening member that is to be introduced into the fastening member, the cooperating fastening member, in order to be able to hook into the attachment passage, changes direction two times. A similar change in direction must also be carried out when the fastening members are disconnected. However, during use of the tire chain, the cooperating fastening member cannot accidentally carry out such movements. Furthermore, accidental unhooking of the cooperating fastening member is prevented by the projection, which the cooperating fastening member engages when it is pushed in the direction opposite to the hooking-in direction, and in the region of which the open width of the attachment passage is only slightly greater than the thickness of the cooperating fastening member.
An object of the present invention is to improve a fastening member of the aforementioned general type in such a way that a cooperating fastening member can be hooked easily into the attachment passage without getting hung up, yet is reliably protected against accidental unhooking.